Fix supervisor dialog overlay stacking and release metadata

[pallyoung]

Summary

• remove the duplicated intro strip from the desktop supervisor dialog
• ensure scheduled-time picker popovers render above modal overlays
• add a patch changeset for @spencer-kit/coder-studio

Test Plan

• pnpm changeset status
• pnpm --filter @coder-studio/web exec vitest run src/components/ui/modal/index.test.tsx src/components/ui/popover/index.test.tsx src/components/ui/datetime-picker/index.test.tsx src/features/supervisor/components/objective-dialog.test.tsx src/features/supervisor/views/shared/objective-dialog-content.test.tsx src/styles/components.theme.test.ts